The present invention generally relates to a copying apparatus in which optical members such as a lens unit, a mirror, etc. are supported to be movable reciprocatingly along a linear path, and more particularly, to a drive controlling mechanism of the optical members, by which one optical member is driven so as to be brought to a halt at a plurality of predetermined positions.
Conventionally, in copying apparatuses having a plurality of copying magnifications, it has been so arranged that changeover of the magnifications is effected by the following three methods; a method (1) in which not only the lens unit but also the mirror are changed in position so as to change the conjugate distance, a method (2) in which the lens unit is changed in position and is provided with an auxiliary lens for changing the magnification with the conjugate distance being maintained constant, and a method (3) in which a zoom lens is employed or the lens unit itself is replaced.
In the method (3), the zoom lens or a plurality of lens units for corresponding magnifications are required to be provided, thus resulting in increase of production cost. Meanwhile, in the methods (1) and (2), either the lens unit and the mirror or the lens unit only is required to be moved to a plurality of positions corresponding to respective magnifications.
In conventional drive controlling mechanisms of optical members such as a lens unit, a mirror, etc., it has been generally so arranged that, when one optical member moved by a motor comes into contact with the stopper members provided at predetermined positions corresponding to respective magnifications, power supply to the motor is shut off through switch members to be actuated by the optical members, as disclosed in U.S. Pat. No. 4,219,273.
However, such prior art drive controlling mechanisms have such an inconvenience that a plurality of stopper members and switch members equal, in number, to the stop positions of the optical member are required to be provided and to be adjusted to each other so that the switch members may be actuated so as to shut off power supply to the motor exactly when the optical member has been brought to a halt through contact of the optical member by the stopper members.
Meanwhile, it is to be noted that the copying magnification is required to be changed variously in accordance with practice of each country or at users' request even in the case of a copying apparatus of the same model. For example, the reduction ratio of 0.64 is generally adopted in the U.S.A., but the reduction ratio of 0.7 or 0.8 is generally employed in Japan or European countries. The above described conventional drive controlling mechanisms are disadvantageous in that all the stopper members and the switch members are required to be adjusted to each other in accordance with such changes of the magnification. Namely, prior art drive controlling mechanisms have such disadvantages that a plurality of stopper members and switch members equal, in number, to copying magnifications are required to be provided and further, assembly and adjustment thereof are extremely complicated.